Hot start issues

[pj31704]

So I have fixed the problems I was having with starting the rig, replaced fuel pump, fuel filter, had to reroute fuel line because of vapor lock issues. Now I have noticed that after engine is hot it either won't start up again or will start but stall out after a few minutes while idling. Engine starts to sputter, if i give it gas it will stay running, but once I lay off the pedal rpm's drop and engine sputters and dies on me. Not sure if possibly has something to do with electric choke? Anyone experienced issues similar? Thanks for any advice

 

[Rons beast]

Hey pj,

If the engine is hot it doesn't need the choke. It could be an adjustment. Adjust the choke to be fully closed when the engine is true cold. (sitting all night, of after a few hours.) Fully closed, with just a very light spring tension, is good for summers in Texas.

Be sure the choke pull-off is working after adjustment. ( after startup, engine vacuum should crack open the chokes about 1/8" when true cold.)

Good Luck

 

[Seabronc]

How old is the carb? Has it been cleaned or rebuilt lately? What carb is installed?

>-

 

[pj31704]

I recently purchased the truck but the carb looks brand new, its a 4 barrel Edelbrock carb. Some other things I have noticed while trying to start while engine is hot, twice now the truck will seem to get stuck in start position. I turn key and it just keeps cranking, even when I turn key to off. I even pulled key out and it still was trying to start. Battery finally died before it shut off. Happened to me once again after that, but I was able to wiggle ignition switch and it shut off. So is the ignition getting too warm while truck is hot? I have also noticed the electric choke is hooked up to the "+" side of the ignition coil. I heard that the power wire to the electric choke should be hooked up to the accessory fuse in fuse box. Could this be a part of the issue?

Attached are the pics of the carb. I am not completely sure it is tuned correctly or if the choke is hooked up wrong. I'd appreciate any advice. Would be nice to get this problem fixed.

 

[Rons beast]

Hey pj,

The engine continuing to start problem has to be fixed. This will ruin starters and batteries, and can be dangerous.

The fix can be simple. The ignition switch, (attached to the steering column, about 3/4 way down)not the key cylinder, should be adjusted. Loosen the 2 screws that hold it and move it slightly down the column. We are talking fractions of an inch. Maybe 1/8". See if this cures the problem. If you get to the maxium adjustment and the problem remains, replace the switch. There may be a problem in the column, buy let's concentrate on the most likely issues first.

Next, the power to the choke is ok comming from the + side of the coil, IF that side has 12v and not a reduced voltage because you are running a points distributor. ( I don't know off the top if a 73 had electronics yet.) maybe some others ( Bully..SB...M5???)can tell us, or you measure the V and tell us.

Do not tie it to the accessory fuse, as most of these are hot when the key is in the ACC position. So you turn off the truck and turn on the acc to listen to the radio, while your wife/ GF "runs in the store" on a cold Texas night. The truck is hard to start when she comes out, because the choke is getting energised the whole time. It should be on a circuit that gets 12v and is energised only when the ignition is on.

Also in your pics I noticed the coil is grounded to itself. Not good....find a good ground to the frame or all the way back to a good ground post or the battery. The carb and choke are somewhat insulated by gaskets. Don't rely on contact just through the screws.

Good Luck

 

[Bully Bob]

YEP..!

Like Ron said.., (but, I think he's refering to a later model column.) That lack of shutting off can be dangerous on many levels.

(Un-hook the bat. cable when work'n on the ign. switch as well.)

'75 was the change to elect. ign. However transplants are not uncommon.

"So is the ignition getting too warm while truck is hot?"

No.

The choke is open/off in those pics.